Chromium(III) Complexation to Natural Organic Matter: Mechanisms and Modeling

Gustafsson, Jon Petter; Persson, Ingmar; Oromieh, Aidin Geranmayeh; Schaik, Joris W. J. van; Sjöstedt, Carin; Kleja, Dan Berggren

doi:10.1021/es404557e

Cited by 170 publications

(126 citation statements)

References 48 publications

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“…As for isolated HA and FA, the mor and peat samples showed a pH dependent sorption behavior, giving a lower silver solubility with increasing pH (Figure 2). At the highest pH values the silver solubility increased again, probably due to the increasing solubility of NOM with increasing pH (from 14 to 106 mg L -1 in mor suspensions and from 13 to 29 mg C L -1 in peat suspensions), which favored complexation reactions in the solution phase 41 . The SHM was unable to predict the solubility of silver using the generic binding parameters of HA and FA, giving too high solubility at pH <5.…”

Section: Resultsmentioning

confidence: 99%

Silver(I) Binding Properties of Organic Soil Materials Are Different from Those of Isolated Humic Substances

Kleja

Nakata

Persson

et al. 2016

Environ. Sci. Technol.

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The solubility of silver(I) in many soils is controlled by complexation reactions with organic matter. In this work we have compared the ability of isolated humic and fulvic acids to bind silver(I) with that of mor and peat materials. One new data set for Suwannee River Fulvic Acid was produced, which was consistent with published data sets for isolated fulvic and humic acids. The ability of soil materials to bind silver(I) was studied as a function of pH in the range 2.5-5.0, at a wide range of silver(I)-to-soil ratios (10(-4.2) - 10(-1.9) mol kg(-1)). By calibrating the Stockholm Humic Model on the humic and fulvic acids data sets, we showed that binding of silver(I) to both types of soil materials was much stronger (up to 2 orders of magnitude) than predicted from the silver(I) binding properties of the isolated humic materials. Thus, the approach taken for many other metals, that is, to model solubility in soils by using metal and proton binding parameters derived from isolated humic and fulvic acids, cannot be used for silver(I). One possible explanation for the discrepancy could be that silver(I) predominately interacted with various biomolecules in the soil samples, instead of humic- and fulvic-acid type materials.

QC 20160913

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Section: Resultsmentioning

confidence: 99%

Silver(I) Binding Properties of Organic Soil Materials Are Different from Those of Isolated Humic Substances

Kleja

Nakata

Persson

et al. 2016

Environ. Sci. Technol.

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QC 20160913

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“…Many studies have reported that NOM may affect the toxicity of nanoparticles by forming NOM-nanoparticle composites [1], may interact with inorganic contaminant in the environment to affect its environmental behavior [2], and may be a source of new contaminants during the chlorination processes of drinking water [3,4]. Because NOM molecules play a pivotal role in the cycling and transport of elements in the ecosphere and have other effects on the environmental quality, it is important for environmental chemists to better understand the molecular composition and transformation of NOM.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive characterization of natural organic matter by MALDI- and ESI-Fourier transform ion cyclotron resonance mass spectrometry

Cao

Huang

et al. 2015

Analytica Chimica Acta

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A B S T R A C TNatural organic matter (NOM) is a complex and non-uniform mixture of organic compounds which plays an important role in environmental processes. Due to the complexity, it is challenging to obtain fully detailed structural information about NOM. Although Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) has been demonstrated to be a powerful tool for providing molecular information about NOM, multiple ionization methods are needed for comprehensive characterization of NOM at the molecular level considering the ionizing selectivity of different ionization methods. This paper reports the first use of matrix assisted laser desorption/ionization (MALDI) method coupled with FT-ICR-MS for molecular characterization of NOM within a mass range of 200-800 Da. The mass spectral data obtained by MALDI were systematically compared with data generated by electrospray ionization (ESI). It showed that complementary molecular information about NOM which could not be detected by ESI, were provided by MALDI. More unsaturated and aromatic constituents of NOM with lower O/C ratio (O/C ratio < 0.5) were preferentially ionized in MALDI negative mode, whereas more polar constituents of NOM with higher O/C ratio were preferentially ionized in ESI negative mode. Molecular anions of NOM appearing at even m/z in MALDI negative ion mode were detected. The results show that NOM molecules with aromatic structures, moderate O/C ratio (0.7 > O/C ratio > 0.25) and lower H/C ratio were liable to form molecular anions at even m/z, whereas those with higher H/C ratio are more likely to form deprotonated ions at odd m/z. It is speculated that almost half of the NOM molecules identified by MALDI may be aromatic or condensed aromatic compounds with

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“…Complexation of the metals with DOC was modelled using the 'Stockholm humic model' (SHM) (Gustafsson et al 2014) with its default database. The DOC and major anions were not measured during the field campaign in 2012.…”

Section: Modelling Approachmentioning

confidence: 99%

Speciation and hydrological transport of metals in non-acidic river systems of the Lake Baikal basin: Field data and model predictions

et al. 2016

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The speciation of metals in aqueous systems is central to understanding their mobility, bioavailability, toxicity and fate. Although several geochemical speciation models exist for metals, the equilibrium conditions assumed by many of them may not prevail in field-scale hydrological systems with flowing water. Furthermore, the dominant processes and/or process rates in non-acidic systems might differ from well-studied acidic systems. We here aim to increase knowledge on geochemical processes controlling speciation and transport of metals under nonacidic river conditions. Specifically, we evaluate the predictive capacity of a speciation model to novel measurements of multiple metals and their partitioning, under highpH conditions in mining zones within the Lake Baikal basin. The mining zones are potential hotspots for increasing metal loads to downstream river systems. Metals released from such upstream regions may be transported all the way to Lake Baikal, where increasing metal contamination of sediments and biota has been reported. Our results show clear agreement between speciation predictions and field measurements of Fe, V, Pb and Zn, suggesting that the partitioning of these metals mainly was governed by equilibrium geochemistry under the studied conditions. Systematic over-predictions of dissolved Cr, Cu and Mo by the model were observed, which might be corrected by improving the adsorption database for hydroxyapatite because that mineral likely controls the solubility of these metals. Additionally, metal complexation by dissolved organic matter is a key parameter that needs continued monitoring in the Lake Baikal basin because dependable predictions could not be made without considering its variability. Finally, our investigation indicates that further model development is needed for accurate As speciation predictions under non-acidic conditions, which is crucial for improved health risk assessments on this contaminant.

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Chromium(III) Complexation to Natural Organic Matter: Mechanisms and Modeling

Abstract: 26Chromium is a common soil contaminant, and it often exists as chromium(III). However,

Cited by 170 publications

References 48 publications

Silver(I) Binding Properties of Organic Soil Materials Are Different from Those of Isolated Humic Substances

Silver(I) Binding Properties of Organic Soil Materials Are Different from Those of Isolated Humic Substances

Comprehensive characterization of natural organic matter by MALDI- and ESI-Fourier transform ion cyclotron resonance mass spectrometry

Speciation and hydrological transport of metals in non-acidic river systems of the Lake Baikal basin: Field data and model predictions

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